Pronunciation: (plum),[key] —n. 1. a small mass of lead or other heavy material, as that suspended by a line and used to measure the depth of water or to ascertain a vertical line. Cf. plumb line. 2. out of or off plumb, not corresponding to the perpendicular; out of true.
—adj. 1. true according to a plumb line; perpendicular.
2. Informal.downright or absolute.
—adv. 1. in a perpendicular or vertical direction.
2. exactly, precisely, or directly.
3. Informal.completely or absolutely: She was plumb mad. You're plumb right.
—v.t. 1. to test or adjust by a plumb line.
2. to make vertical.
3. Shipbuilding.horn (def. 35).
4. to sound with or as with a plumb line.
5. to measure (depth) by sounding.
6. to examine closely in order to discover or understand: to plumb someone's thoughts. 7. to seal with lead.
8. to weight with lead.
9. to provide (a house, building, apartment, etc.) with plumbing.
—v.i. to work as a plumber. Also,plum(for defs. 3–7).
Pronunciation: (plum),[key] —n. J(ohn) H(arold), 1911-2001, British historian.